Dual lumen catheter with contrastradiography sections to identify the lumens

ABSTRACT

A catheter has an outer peripheral portion ( 15 ) in the form of a tube and an internal, wall ( 16, 26 ) within the tube forming a plurality of lumens ( 11   a,    11   b,    21   a,    21   b ). Axially extending linear contrastradiography sections (17 a,    17   b,    27   a,    27   b ) of radiopaque material are formed at a plurality of intersection points between the outer peripheral section and the wall, the peripheral extent (a, b) of the respective contrastradiography sections being different.

The present invention relates to a catheter for placement in a bloodvessel to supply a medicinal fluid or a nutritional supplement to apatient.

It is well known to provide a person (hereinafter referred to as apatient) with decreased oral ingestion function, for example due to oldage or disease, with a medicinal fluid or a nutritional supplement for ahigh-calorie infusion through a blood vessel by means of a catheter. Itis known to confirm the position of the catheter by incorporating aradiopaque agent (see, for example, JP-U-51 108 389). Such a catheter isformed of a flexible plastic tube and has a section which extends in theaxial direction of the plastic tube and which incorporates a radiopaqueagent. The radiopaque agent conventionally extends in a circumferentialdirection around the wall of the plastic tube. Therefore, in a situationwhere the catheter has been placed in a blood vessel of the patient, theposition of the catheter can be confirmed by irradiating X-rays to forman image of the radiopaque agent.

Included among these catheters are double lumen catheters which have twolumens, that is a main lumen and a sublumen, to supply differentmedicinal fluids through the respective lumens, and also cathetershaving more than two lumens. However, in such catheters, when thethickness of the section incorporating the radiopaque agent is small, itis difficult to confirm the position of the catheter because theradiographic contrast is reduced. Therefore, in order to improve theradiographic contrast for detecting the radiopaque agent, it isnecessary to increase the cross-sectional area (thickness) of thesection incorporating the radiopaque agent. However, when thecross-sectional area of the section incorporating the radiopaque agentis increased, there are problems in that the strength of the catheter isreduced, and it is difficult to confirm that the medicinal fluids arepassing through the catheter.

Further, it has been proposed for double lumen catheters to incorporatea narrow section incorporating radiopaque agent at two different regionscorresponding to the main lumen and the sublumen. However, in this case,it is difficult to distinguish between the main lumen and the sublumenso that the effectiveness is reduced at the time when the catheter isassembled during manufacture. Specifically, during manufacture of thecatheter, even though different members, such as adapters, are connectedto the main lumen, and the sublumen, it is difficult to distinguishbetween the main lumen and the sublumen and the operation is laborious.

It is an object of the present invention to provide a catheter whichimproves the effectiveness of contrastradiography and which, at the sametime, does not reduce the effectiveness at the time when the catheter ismanufactured.

According to the present invention there is provided a catheter havingan outer peripheral portion in the form of a tube and an internal wallwithin the tube forming a plurality of lumens, wherein axially extendinglinear contrastradiography sections of radiopaque material are formed ata plurality of intersection points between the outer peripheral sectionand the wall, the peripheral extent of the respectivecontrastradiography sections being different.

Because the contrastradiography sections are formed at the plurality ofintersection points, the contrastradiographic property can be improveddue to the plurality of the contrastradiography sections. Further,because the peripheral extent (width) of the respectivecontrastradiography sections is different, it is possible to distinguishthe respective lumens corresponding to the contrastradiography sections.The different peripheral extent of the contrastradiography sections canreadily be effected during manufacture and the ease of use of thecatheter can be improved. Furthermore, since the contrastradiographysections are formed at the intersection points of the outer peripheralsections and the wall, the passage of medicinal fluids through thecatheter can readily be confirmed. In particular in the case where morethan two lumens are provided, the contrastradiography sections need notbe formed at all of the intersection points, but at only selectedintersection points.

A single internal wall may be provided so as to form two lumens withfirst and second contrastradiography sections, the ratio of theperipheral extent of one of the first and second sections to theperipheral extent of the other of the first and second sections being inthe range from 1:3 to 2:3. In one embodiment of the invention the ratiomay be substantially 1:2.

In this way it is possible to correctly distinguish between the twocontrastradiography sections so as to easily discriminate the respectivelumens. Further, by setting the ratio of the peripheral extent of thetwo linear contrastradiography sections to the above values, a cathetercan be obtained, the location of which can be determined with precisionand through which the passage of medicinal fluids can be confirmed.

In at least one of the contrastradiography sections the radiopaquematerial extends into the wall. A contrastradiography section may heformed within the wall.

In this case, the radiographic contrast of the catheter with respect toX-rays is improved, while the passage of medicinal fluids through thelumens can readily be confirmed.

A further linear contrastradiography section may be formed solely withinthe outer peripheral section.

The radiopaque material may be wholly embedded within the catheter.

Therefore, since the radiopaque material is not exposed, deteriorationor stripping can be avoided. For example, in the event that thecontrastradiography section is formed of a mixture of barium sulfate anda polyurethane resin, any exposed material deteriorates as a result ofcontact with alcohol.

For a better understanding of the present invention and to show moreclearly how it may be carried into effect reference will now be made, byway of example, to the accompanying drawings in which:

FIG. 1 is a plan view of a double lumen catheter according to a firstembodiment of the present invention;

FIG. 2 is a plan view of a catheter main body of the double lumencatheter shown in FIG. 1;

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2; and

FIG. 4 is a cross-sectional view of a catheter main body of a doublelumen catheter according to a second embodiment of the presentinvention.

A first embodiment of the catheter according to the invention will nowbe explained with reference to accompanying drawings. FIG. 1 shows adouble lumen catheter 10 which includes a catheter main body 11 formedof a long flexible tube, a connecting member 12, a pair of connectingtube members 13 a and 13 b which are formed of flexible tubes, and apair of lure adapters 14 a and 14 b.

The catheter main body 11 is formed of a soft polyurethane resin and, asshown in FIGS. 2 and 3, is in the form of a tube having a cylindricalouter peripheral section 15 with a substantially diametrically extendingwall 16 to divide the outer peripheral section 15 internally into twoparts. The wall 16 forms two lumens, a main lumen 11 a and a sublumen 11b, within the outer peripheral section 15. Where the outer peripheralsection 15 and the wall 16 intersect, linear contrastradiographysections 17 a and 17 b, of contrastradiographic material, are providedin the catheter body so as to extend in the longitudinal direction ofthe catheter main body 11.

A mixture of white barium sulfate and a polyurethane resin is employedin that part of the polyurethane resin in the linear contrastradiographysections 17 a and 17 b in such a manner that the barium sulfate is notexposed at the surfaces of the outer peripheral section 15 or of thewall 16. The width a of a portion of the linear contrastradiographysection. 17 a along the outer peripheral section 15 is set to be largerthan the width b of a portion of the linear contrastradiography section17 b along the outer peripheral section 15. The ratio of the width a ofthe linear contrastradiography section 17 a to the width b of the linearcontrastradiography section 17 b is set to be approximately 1:2.Further, inner central portions of both linear contrastradiographysections 17 a and 17 b protrude a short distance internally of the wall16 (the center of the outer peripheral section 15).

A leading end of the catheter main body 11 is provided with an opening11 c having a tapered outer peripheral, surface, and a rear end of thecatheter body 11 is divided into a main outer peripheral section 15 aand a sub outer peripheral section 15 b which are separated from eachother in order to separate the main lumen 11 a and the sublumen 11 b.Therefore, a rear end of the main peripheral section 15 a and a rear endof the sub peripheral section 15 b can be connected to connecting tubemembers 13 a and 13 b by means of a connecting member 12, respectively.

The connecting tube members 13 a and 13 b are in the form of tubes whichare made of a soft polyurethane resin and the outer diameters of whichare larger than that of the catheter main body 11. In, order todistinguish the connecting tube members 13 e and 13 b, the connectingtube member 13 a is blue, and the connecting tube member 13 b iscolorless. Further, the connecting member 12 is formed of a softpolyurethane resin, and has a connection portion which is secured aroundthe connection portion of the main peripheral section 15 a and the subperipheral section 15 b and also around the connecting tube members 13 aand 13 b.

The connecting member 12 is substantially triangular in shape, a portionconnected with the main peripheral section 15 a and the sub peripheralsection 15 b being relatively narrow, and a portion connected with theconnecting tube members 13 a and 13 b being relatively wide. Pathwaysare formed in the connecting member 12 to connect the main peripheralsection 15 a with the connecting tube member 13 a and to connect the subperipheral section 15 b with the connecting tube member 13 b.

The lure adapters 14 a and 14 b are made of polyurethane resin and havethe same structure. The lure adapter 14 a includes a tube fixing section18 a, a grasping section 19 a, and a medicinal fluid injecting section20 a, while the lure adapter 14 b includes a tube fixing section 18 b, agrasping section 19 b, and a medicinal fluid injecting section 20 b. Thetube fixing section lea is fixed to the rear end of the connecting tubemember 13 a, and the tube fixing section 18 b is fixed to the rear endof the connecting tube member 13 b.

The grasping sections 19 a and 19 b are detachably attached to the tubefixing sections 18 a and 18 b by way of screw-threaded portions (notshown), respectively. When an operator manipulates the double lumencatheter 10, he can grasp the grasping sections 19 a and 19 b. Further,the medicinal fluid injecting sections 20 a and 20 b are fixed to thegrasping sections 19 a and 19 b, respectively and have a soft elastomerattached thereto. When supplying the medicinal fluid into the doublelumen catheter 10, an injecting section of an infusion line (not shown)is inserted into the elastomer of the medicinal injecting sections 20 aand 20 b to inject the medicinal fluid. Furthermore, since the medicinalfluid passes through the double lumen catheter 10, in order to see themedicinal fluid therein, portions other than the lure adapters 14 a and14 b are formed of transparent materials.

As mentioned above, when supplying two kinds of medicinal fluids into abody of a patient through a blood vessel (not shown) using the doublelumen catheter 10, firstly a cannula punctures the blood vessel.Thereafter, the opening 11 c formed at the leading end of the doublelumen catheter 10 is inserted into the cannula that is already placed inthe blood vessel so as to be placed into a target position in the bloodvessel. Thereafter, when the opening 11 c of the double lumen catheter10 reaches the target position, the cannula is removed from the bloodvessel. During that time, it is required to be able to prevent deviationof the double lumen catheter 10 ad to confirm that the opening lie ofthe double lumen catheter 10 is at the target position. Since the linearcontrastradiography sections 17 a and 17 b are formed of a materialwhich does not transmit X-rays, confirmation is performed by forming animage.

After the double lumen catheter 10 is placed in the blood vessel, themedicinal fluid injecting sections 20 a and 20 b are connected to apredetermined infusion line to begin injecting the medicinal fluid. Thusthe medicinal fluids enter the body of the patient through the bloodvessel. In this case, since the linear contrastradiography sections 17 aand 17 b occupy a small portion of the outer peripheral section 15 ofthe catheter main body 11, it is possible to confirm that the medicinalfluids are passing through the main lumen lie and the sublumen 11 b. Inthis case, confirmation that the medicinal fluids can be accomplished byviewing a portion of the outer peripheral section 15 of the cathetermain body 11 which is located externally of the patient's body.

During manufacture of the double lumen catheter 10, the linearcontrastradiography sections 17 a and 17 b are formed with differentwidths so as to function as differentiating markers. In this way, theconnection of the main outer peripheral section 15 a to the connectingtube member 13 a and the connection of the sub outer peripheral section15 b to the connecting tube member 13 b are satisfactorily performed.Further, the connection of the connecting tube members 13 a and 13 b tothe lure adapters 14 a and 14 b is also satisfactorily performed.Therefore, it is possible to improve the effectiveness of the catheter.

As mentioned above, since in the double lumen catheter 10 the linearcontrastradiography sections 17 a and 17 b are formed at intersectionpoints of the outer peripheral section 15 and the wall 16 of thecatheter main body 11, it is possible to confirm the position of thedouble lumen catheter 10 by radiography. Further, in this case, sincethe widths of the linear contrastradiography sections 17 a and 17 b aredifferent from each other, it is possible to distinguish the main lumen11 a and the sublumen 11 b on the basis of the difference.

Furthermore, because the linear contrastradiography sections 17 a and 17b are formed only at the intersection points of the outer peripheralsection 15 and the wall 16, readily possible to confirm that medicinalfluids are passing through the main lumen 11 a and the sublumen 11 b,respectively. Because the linear contrastradiography sections 17 a and17 b are arranged within the outer peripheral section 15 not to heexposed at the surface thereof, it is further possible to preventdeterioration or stripping thereof. Therefore, the useful life of thedouble lumen catheter 10 can be increased.

FIG. 4 shows a section through a catheter main body 21 of a double lumencatheter according to a second embodiment of the invention. In thiscatheter main body 21, a linear contrastradiography section 27 c isadditionally formed in a wall 26. The linear contrastradiography section27 c is integrally connected to the linear contrastradiography sections27 a and 27 b which are formed at the intersection points of an outerperipheral section 25 and the wall 26. Therefore, due to the wall 26 twolumens, in the form of a main lumen 21 a and a sublumen 21 b, are formedin the catheter main body 21. The remaining structure of the doublelumen catheter is similar to the double lumen catheter 10 describedabove in relation to FIGS. 1 to 3.

According to the double lumen catheter of FIG. 4, it is possible morereadily to confirm the position of the catheter main body 21 and todistinguish between the main lumen 21 a and, the sublumen 21 b. Further,it remains possible readily to confirm that medicinal fluids are passingthrough the main lumen 21 a and the sublumen 21 b. The other effects ofthe double lumen catheter are similar to the double lumen catheter 10described above in relation to FIGS. 1 to 3.

Further, the catheter according to the present invention is not limitedto the above-described embodiments, and appropriate modifications may bemade. For example, in the above embodiments, even though the ratio ofthe width a of the linear contrastradiography section 17 a to the widthb of the linear contrastradiography section 17 b and the ratio of thewidth a of the linear contrastradiography section 27 a to the width b ofthe linear contrastradiography section 27 b are set to be approximately1:2, the ratio is not limited thereto, and may be changed, In this case,the width ratio of the respective linear contrastradiography sectionscan be set to any suitable predetermined value, preferably in the rangefrom 1:3 to 2:3.

Furthermore, the present invention is not limited to use in double lumencatheters, but can be used in other multi-lumen catheters, such astriple lumen catheters or catheters incorporating more than threelumens. In this case, the linear contrastradiography sections do notneed to be provided at all of the intersection points of the outerperipheral section and the wall, but can be provided at selectedintersection points.

The linear contrastradiography sections 17 a and 17 b extend partlyaround outer peripheral section 15 and partly within the wall 16 in thefirst embodiment and the linear contrastradiography sections 27 a, 27 b,and 27 c extend partly around the outer peripheral section 15 and theentire extent of the wall 16 in the second embodiment. However, thelinear contrastradiography sections need only be formed in the outerperipheral section 15. In this case, the linear contrastradiographysection 27 c is not provided. Further, it may be preferable that one ofthe linear contrastradiography sections, for example the linearcontrastradiography section 17 a, is formed in both the outer peripheralsection 15 and the wail 16, and the other linear contrastradiographysection 17 b is formed only in the outer peripheral section 15.Furthermore, in a catheter having three or more lumens, it may bepreferable that one linear contrastradiography section is formed in boththe outer peripheral section and the wall, and the remaining linearcontrastradiography sections are formed only in the outer peripheralsection.

In the above-described embodiments, even though the main lumen 11 a andthe sublumen 11 b, and the main lumen 21 a and the sublumen 21 b, havesubstantially same size, the sizes of the lumens and sublumens may bedetermined appropriately. For example, the main lumen may have arelatively large cross-sectional area, and the sublumen may have arelatively small cross-sectional area. Further, the shape or the size ofthe respective linear contrastradiography sections, and the material,the shape, and the size of the members forming the respective sectionsof the catheter may be appropriately modified.

1-7. (canceled)
 8. A catheter comprising: a catheter main body having afirst and second end, the catheter main body including an outerperipheral section and an internal wall intersecting the outerperipheral section to define first and second lumens extending along alongitudinal axis defined by the catheter main body; and first andsecond contrastradiography sections disposed at least within the outerperipheral section, at the intersection of the outer peripheral sectionand the internal wall, and the first and second contrastradiographysections defining respective first and second different peripheralextents.
 9. The catheter of claim 8, wherein the first lumen has alarger cross-sectional area than the second lumen.
 10. The catheter ofclaim 8, wherein the first and second contrastradiography sections arediametrically opposed relative to one another.
 11. The catheter of claim8, wherein the first and second contrastradiography sections togetherextend over less than an entirety of the outer peripheral section. 12.The catheter of claim 8, wherein the first and secondcontrastradiography sections extend substantially linearly along anaxial portion of the catheter main body.
 13. The catheter of claim 8,wherein respective inner central portions of the first and secondcontrastradiography sections protrude into the internal wall.
 14. Thecatheter of claim 8, wherein the catheter main body is polyurethane withradiopaque material disposed in the first and second contrastradiographysections.
 15. The catheter of claim 8, wherein each of the first andsecond contrastradiographic sections is a mixture of white bariumsulfate and a polyurethane resin.
 16. The catheter of claim 8, whereinthe ratio of the first peripheral extent of the firstcontrastradiography section to the second peripheral extent of thesecond contrastradiography section ranges from about 1:3 to about 2:3.17. A method of using a catheter, the method comprising: placing acatheter in a blood vessel of a patient, the catheter including aninternal wall and an outer peripheral section, the intersection of theinternal wall and the outer peripheral section defining a first lumenand a second lumen; and distinguishing the first lumen from the secondlumen based on differing peripheral extents of respective first andsecond contrastradiography sections disposed at least within the outerperipheral section, at an intersection of the outer peripheral sectionand the internal wall.
 18. The method of claim 17, further comprisingplacing an opening defined by the catheter at a target position withinthe blood vessel, the placement of the opening based, at least in part,on distinguishing the first lumen from the second lumen based ondiffering peripheral extents.
 19. The method of claim 17, wherein thefirst lumen has a larger cross-sectional area than the second lumen. 20.The method of claim 17, wherein the first and second contrastradiographysections are diametrically opposed relative to one another.
 21. Themethod of claim 17, wherein the first and second contrastradiographysections together extend over less than an entirety of the outerperipheral section.
 22. The method of claim 17, wherein the ratio of thefirst peripheral extent of the first contrastradiography section to thesecond peripheral extent of the second contrastradiography sectionranges from about 1:3 to about 2:3.